Generally, the pin layout of any conventional FPC golden finger is manufactured basing upon the dimensions defined in it complementary connectors' specifications that are currently available on the market, especially for the dimensions specifications regarding to pin width and pin pitches. For mating a FPC golden finger with its complementary connector perfectly without causing any shortage between the contact pins of the connector and the internal pins of the golden finger, the pin layout of the golden finger must be manufactured with high accuracy and minimized tolerance.
Following the trend that more and more connectors are designed with more pins for connection, the size of the golden finger is increasing consequently. Despite of the increasing size, for ensuring no erroneous contact between neighboring pins while inserting a large-sized golden finger into its complementary connector, such golden finger must be manufactured with high accuracy especially for its pin layout. However, the cost for some manufacturers to maintain such high manufacturing accuracy is low production yield. On the other hand, the trade off for other manufacturers capable of maintaining such manufacturing accuracy is that the manufacturing cost of FPC with such golden fingers is increased. In addition, the alternating routings of the pins formed on the golden finger may be damaged or even broken while the FPC is bended by an external force.
Please refer to FIG. 1A and FIG. 1B, which are a top view and a cross-sectional view of a conventional pin layout of a golden finger for flexible printed circuitboard. From top to bottom that the golden finger 1 is configured with a protective layer 10, a copper layer 11, a substrate 12, another copper layer 13, another protective layer 14, and a stiffening plate 15. It is noted that the interlaced pins on the golden finger 1 for mating with its complementary connector is formed by the etching of the copper layer 11, whereas the pins 111 are odd-numbered pins while the pins 112 are even-numbered pins. As shown in FIG. 1A, portions of those odd-numbered pins 111, as the portion 1110 enclosed by the dotted line for illustration, are narrowed to be arranged alternating with the even-numbered pins 112. However, since the aforesaid pin layout is without exception that it is troubled by the conventional problems regarding to manufacture accuracy and pin width, such thin routings at the portions 1110 can either be damaged or even broken while the FPC is bended by an external force, or cause shortage as they are easy to contact erroneously with their neighboring pins.
Please refer to FIG. 2A and FIG. 2B, which are a top view and a cross-sectional view of another conventional pin layout of a golden finger for flexible printed circuitboard. From top to bottom that the golden finger 2 is configured with a protective layer 20, a copper layer 21, a substrate 22, another copper layer 23, another protective layer 24, and a stiffening plate 25. It is noted that the pins of the golden finger 2, including the odd-numbered pins 211 and even-numbered pins 212, are formed by an electroplating means. Similarly, portions of those odd-numbered pins 211, as the portion 2110 as well as the thin lines formed in front of those pins enclosed by the dotted line for illustration, are narrowed to be arranged alternating with the even-numbered pins 212. However, since the aforesaid pin layout is without exception that it is troubled by the conventional problems regarding to manufacture accuracy and pin width, such thin routings at the portions 2110 can either be damaged or even broken while the FPC is bended by an external force, or cause shortage as they are easy to contact erroneously with their neighboring pins
Therefore, it is in need of a FPC golden finger having pin layout with multi-layered routings.